Voltage controller



June 9, 1953 R. J. c. RoQuET l 2,541,739

. VOLTAGE coN'rROLLER Filed July 28, 1948 v 2 Sheetg-Sheet 1 :Er i lNvENroR nAkMo/vo l c. ROQUET AGENTS June 9, 1953 R. J. c. RoQuEr 2,641,739,

VOLTAGE CONTROLLER Filed July 28, 1948 2 Sheets-Sheet 2 INVENTOR` 7 f A @Amo/vo z c. ROQUE-r BY )quali-uu, cul @y AGENTS` Patented June 9, 1953 UNITED 'STATES PATE-Nr oFFica Application July l28, 1948, Serial No. 41,289 f f In France August 27, 1947 The present invention has for its object a device to allow reversing the difference of potential produced by a source at the input terminalsof an electric circuit by means of ya reverser, while keeping between said terminals the constancy of said diierence of potential in terms of the modulus, in' spite of the internal resistance of the source.

It applies in particular, to signalling and telegraphy where the difference of potential at vthe input of aworkingcircuit must be reversed and Where the constant of this diierence of potential (in modulus) is of prime importance, even if the strength is not the same for the two directions of the current and even if the quantity of current is different for these two directions of the current during a period of operation.

V`The invention will now loe-described in its application to telegraphy, Without the scope of the invention being limited to this particular use.

The usual means for reversing the direction of the current in a transmission channel in bivalent modulation and vwithdouble current, consistsin having two sources, each for one direction of the current, one or the other being put in circuit by., the signals transmitting member. Experience 8 Claims. (CL 323-7 5) proves and theory confirms that if the two sources arey storage batteries, the quantities of current they deliver during the course of a period .ofoperation being not equal, their E. M..F.s are not, or do not remain equal (in modulus) and that, if the sources are not storage batteries and havev a rather high inner impedance, this contributesto- Ward creating a transitory condition which takes place in the transmission channel and may, by its presence, increase'the rate of distortion of the modulation received atulfthe other end of that channel.

The device, the object of the present invention, obviates these drawbacks. It consists in reversing a source oiE; M, F. by means of the usual telegraph transmitter and it includes a set ofresistances and rectifying cells suitably biased by an auxiliary source `whose E.' M. F. may, moreover, vary accidentally (in modulus) in large proportions without perceptibly modifying the current in the line.

f f-In order that the invention maybe more clearly understood, the device will now be described by way of example with reference tothe accompanying drawing, in which Fig. 1 is a wiring diagram of a iirst embodiment, Figs 2 and 3 being partial views of the same diagram in two operative positions,` and Fig. l is asimilar View of amodicai io n. v ligures'v,l (i and? show variationsof the The drawing'oi` the device in its preferred form of embodiment is given in Figl, in which :v y

M is the bivalent modulating telegraphwtransf mitter adapted to take up the positions l and 2 E1, E2, E2 are the sources of M. F. whose E. M. Ffs are respectively er, e2, and e2.

r1, r2, r3 Aare the resistances.

C1, C2, C3, C4 are the rectifyingu'cells.

VT is the telegraph transmission channel Whose input terminals are A; and ng, l Y

i, i', i1, i2, Z3, I, are the current intensities taken in the positive direction oi the arrowsl Y, v

The connections are supposed to be without resistance. Y A g The sources of Edi/i. E. andthe cells are oriented as shown inthe i'lgure.

The modulating transmitter M, called modula-y tor, is a modulator,` ofany model withtwo contacts, or a similarmodulator such asare used on telegraph apparatus` inservice. llhismay, for instance, be a Morse .signalling key or an assembly of two transmitting crowns of the Baudot system or, the transmitting lever and the stops of an arythmic relay; or the moving part and the stops ofan intermediate' relay. Y The source Ei is of any desired nature, provided that its E. M. F. cris constant. The resistance 1'1 represents the internal resistance of said source. `The sourc'e Er will be referred to as standard source.

The sources of E. M. F. E2 and'Ezlv are of any desired nature (batteries, storage batteries,` dry rectiers or lamps, rotary generators, etc.) but having internal resistances nominally equal.

The resistance r2 includes the common internal resistance of these sources. Their E. M. F.s e2 and e2' respectively, nominally equal in modulus, may

be different in fact, in-acertain measurewhichv l considered as zero, to simplify.

Inthe example chosen, to facilitatey the 'description, VT is the telegraph transmission channel but infact VT may include the transmission channelitself` and the shuntings Whichmay possibly be made for controlling the transmitted signals 0r for. any Qtheijiuses. Inamoreeenerl manner, VT must be taken as being the Working Circuit.

It is supposed in fli'stplace, that the inoduL"v 3 lator M whose movable nger is in position l, puts in the circuit, the source E2.

The resistances and the E. M. F.s may -be cletermined so that the electric potential of the point B is higher than that of point E, and that of point F higher than that of point D.

This condition being fulfilled, the cells C1 and C4 let the current pass whilst the cells C2 and Cs present to its flow a Very high resistance, supposed infinitely high, for the sake of simplicity.

The electric network is then in accordance with the diagram of Fig. 2.

ySo that the above conditions may be carried out, it is necessary to adjust the resistances and the E. M. F. either experimentally or else by cal.- culating so that the current I is positive (that is to say that it flows in the direction of the arrow to which it is referred, Figs. 1 and 2).

The input terminals A1 and A2 of the transmission channel are then in direct connection with the source E1 through the single resistance 1'1.

In the second place, it is supposed that the movable part of the modulator M (Fig. 1) upon passage to position 2 puts the source E2' in circuit instead of the source E2, all other things remaining equal.

The E. M. F. e2 in the branch BD (Fig. 1) having been replaced by its reverse e2', the potential of the point D is this time higher than that of the point E, and that of point F is higher than that of point B. A current i' flows in the cells C2 and C3, according to the dottedV line arrows of Fig. l, while no current flows in the cells C1 and C4. The current i is moreover equal to current i.

The electric circuit then corresponds to the diagram of Fig. 3 on which the direction of the arrows of the Fig. l has to be adhered to, as showing the positive direction of the current.

The terminals A1 and A2 (Fig. 3) are still connected with the source E1 through the single resistance 1'1, but with reversal of the connections between EF and BD in relation to the drawings of the Fig. 2.

Thus, when the moving part of the modulator M (Fig. 1) changes its stop contact, the difference of potential between the input terminals A1 and A2 of the channel is reversed and the current I changes direction without their modulus being modified.

If the source E1 shows a negligible internal resistance 1'1, the diiference of potential between B and D remains equal in modulus to e1 and the modulus of the'intensity I is independent of r2, r3 and ez (or ez) provided that the conditions of lgradation of the potential shown for the termi- ;nals B, D, E, F, are adhered to.

If the source E1 has a nonneglgible internal resistance r1, the modulus of I in general depends on r1 unless-the current i1 is zero. Nevertheless the elements entering into the constitution ofV the diagram may be determined so that the intensity i1 remains nominally at zero, and so that in normal service it remains small in any case.

Indicating by R the resistance of the transmission channel whose reactance is omitted, and supposing for instance that ez is the E. M. F. brought into play by the modulator M, the intensities I, z and i1 in permanent operation, are expressed by the following formulas:

to which must be joined the condition (z' o) by The relation (6) being fulfilled, the current intensity flowing in the transmission channel is:

This error is all the more small as r1 is smaller before in r2, r3 and R. It is zero in particular when 1'1- -0, which approximately results in practice if E1 is a storage battery. For instance, if r1 is about a thousandth of r2, ra and R, the relative error Y is about 1%,000 of the relative variation of e2.

According to the expression (6), e2 is always higher than e1, and these two E. M. F.s differ all the more as 1'2 is greater (all other things being equal).

According to the Expression 7, the relative irregularity is all the greater as r2 is smaller (all other things being equal). By means of these two statements, for a given relative irregularity (not to be exceeded) r2 is chosen all the bigger (and eventually es) as the E. M. F. e2 is more irregular.

A source E2 may therefore be used of secondrate quality (high internal resistance, E. M. F.

. irregular) like an alternating current rectifier for instance, provided with a rudimentary filter.` A storage battery may also be used with variable E. M. F. during the course of the discharge, like modulus, having the same expression with the two sources Ez and E2 whose E. M. F.s and inter- AI I as a function of the irregularity of the two sources in relation to one another.

Seeing that in practice that which is above all of importance is that I shall keep the same intensity in modulus when the current is reversed, the Expression 8 gives the relative value of the difference of this intensity at the moment of the reverslng:

(s) I+" E+E+R In this expression, e2-e1 shows the difference of E. M. F. of the two sources, taken in modulus, at the moment of the reversing.

If the sources E2 and E2 had been used directly to transmit signals into the transmission channel according to the classical assembly, without the aid of the device, which is the object of the invention, the relation between the relative diierences of the E. M. F.s and those of the current would have been:

the factor being always lower than 1, the comparisons of the Expressions 8 and 9 brings to light that the device invented gives a means of adjusting by a standard E. M. F. (e1) the voltage between the input terminals A1, A2 of a telegraph transmission channel.

When the Condition 6 is not exactly fulfilled, the current i1 is positive or negative Formula 3 according to the values of the elements in cause: if it ispositive, E1 operates as generator; if it is negative E1 operates as receiver. In certain cases, according to the nature of the source E1 it i's protable to deliberately choose one of these two 'methods of operation rather than the other. For instance, if E1 is a source resulting from rectifying an alternating current by means of rectiying cells, it can only operate as generator. In this case, the assembly elements ycan be determined so that, taking into account the maximum anticipated variations of these elements, the current i1 can only be zero or positive. By way of a second example, if E1 is a storage battery, its conditions of good upkeep demand a certain balance between its functions as generator and receiver. These conditions are fullled either in Ydetermining the assembly elements so that taking into account the maximum anticipated variations of said elements, the current i1 is zero on average, or else in deliberately making one of these elements (for instance ra) variable and by modifying it from time to time, automatically or not. When-the source E1 can operate as receiver permanently, without inconvenience, rand if its internal resistance is zero (or small) ra may be made infinite thus improving the power effi-A ciency of the system. The 'Condition `6 does not need, in this case, to be fullled to obtain However, standard voltage sources are not `as a rule designed to act as permanent receivers of 6. directcurrent and this solution ,is not to be gen'- erally considered in practical cases.

When the Condition 5 is fulfilled, the system l acts as damper of excessive intensity, as is the result of Formula '7 if the excessive intensity is due to an accidental over-voltage of the source placed in the branch BD, or as it would result from a similar and obvious formulav if the excessive intensity is due to an accidental variation of the other elements of the system.

Finally, when the Condition 5 is not fulfilled, the cells are non-conducting and the source E1 is practically cut off from the transmission channel VT, and the source in the branch BD alone delivers then current into the said channel (Figs. 1 and 4). The standard source E1 is then safe from the damages from which it may suffer for instance from a short circuit in the transmission channel. Furthermore, this characteristic may be put to proiit for limiting the current in the transmission channel by suitably determining the elements composing the branch BD.

To simplify the description, it has been supposed that the sources Ez and En are separate as this in fact is the case in the majority of telegraph vsystems in use. They can also be merged in a single source made reversible with the aid of a Wheatstone bridge arrangement.

Fig. 4 gives the wiring diagram. In this iigure:

r2 is a resistance.

n and T5 are resistances of equal value.

Ea is the single source of the branch BD.

V e3 is the E. M. F. of the source Es, P is its internal resistance. The assembly elements other than those which make up the branch BD are the same and are referred to in the same manner as in the Fig. 1.

When the moving part of the modulator M changes its stop, it is known that the difference of potential between the ends B and D of the branch BD undergoes a reversing. The following formulas allow establishing the connection between the E. M. F. e3 and the internal resistance P of the source Ea, the resistances r2 and r4 (or its equal f5) on the one hand (Fig. 4), and the E. M. F. e2 (or its equal ez) and the resistance effect:

This variation of the device has the particular characteristic that within the limits allowed by the precision in the equality of the resistances n and rs and the constancy of the E. M. F. e3. the voltage in the branch BD remains the same in modulus when the modulator M changes position. On the other hand, the task of getting a tolerable power yeiiiciency of the device imposes the choice of high resistances r4 and f5; as a result ra and consequently e2 must lbe relatively high.

The variation will, therefore, be particularly indicated for a very third-rate source Ea. A single source may finally be used in the branch BD, switched over by a reverser accord-ing to a known assembly, or any other device allowing the reversing at will of the difference of bias between 4the points B and D.

Whatever vmay be the diagramV adopted (Fig. 1

'while the rest of theassembly 'is installed near vention is shown on Fig. 5.

The invented device, although applicable in all the cases, is particularly indicated for the units of superphantom and infraacoustic telegraph communications. It obviates the use of relays with double armature or of two reverser relays according to usual form of practice for reversing, under the control of the telegraph apparatus, the voltage applied to the line.

Moreover, a source Ei may be used common to several telegraph transmission channels. Not only does the system according to the invention ensure a constant voltage and without apparent internal resistance at the input of each channel, thus having the advantage of leaving the complete liberty of adjusting the optional trimmer resistances to be placed in line for limiting the current and obviate the disturbances from one channel to another by voltage drop in the source, but it furthermore obviates the drawbacks of accidental misadjustment of these relays and the task of maintenance of their adjustment. Such a variant of 'the invention is shown on Fig. 6. Y

When the reactance of the transmission channel VT is not small it is preferable to replace in the formulas andY in the description, the resistances r2, ra and R by impedances. The conditions must be satisfied, at least approximately, for all the frequencies of the pass band which the channel presents. An embodiment of the invention including such impedances, each made up, by way of example, of a resistance r2, or r3 and of an inductanceLg or Lc, is represented on Fig. '7. On Fig 7 it must be understood that the working circuit VT, represented by its terminalsonly, may include an inductance L in addition toits resistance R.

In general, the reactance of submarine telegraph channels is not small. With the reservation that this must be taken into account, the invention applies likewise to submarine telegraph. However, in this last application, a separate standardsource should be used for each transmission channel.

The device, which is the object of the invention, likewise lends itself to trivalent telegraph modulation, for which the voltage applied to the input oi the channel is at times positive, at times negative, at times Zero, the positive and negative voltages being equal in modulus. If indeed, the modulator (Fig. 1 or 4) in a position not shown, cuts the branch BD or replaces it by a conductor Without E'. M. F. the four cells C1, Cz, C3, C4 become non-conducting No current iows in the transmission channel, and the resistance seen from this channel is that which the modulator has put in circuit between the points B and D instead of the branch BD. Y

Although the present invention has been described in connection with particular examples, it is obviously capable of many variations or modifications, all of which fall within 'the scope .ofthe appended claims.

What is claimed is:

v,1. Voltage reversing and regulating device for applying a direct-current voltage to the input terminals of a working circuit of resistance having a value R, in a direction reversible at will, and for maintaining this voltage constant in absolute value irrespective of its direction of application, said device comprising a source of standard direct current voltage of value e1, a plurality of auxiliary sources of direct-current voltage average of value e2 but whose actual voltage may appreciably differ from e2, a connecting-circuit for connecting one selected at will of said auxiliaryl sources of average voltage e2 on one side directly to one of the terminals of above-said working circuit and on the other side to one of the terminals of a second resistance of value r2, the first terminal of which is connected to the second terminal of said working circuit, a circuit arranged in a Wheatstone bridge having each of its arms constituted by an element of a symmetrical electric conductivity connected in such a direction that current rlow through an external circuit connected to a rstpair of arm junction points of said Wheatstone bridge is possible only in one direction, the second pair of arm junction points of said Wheatstone bridge being connected to said working circuit, a second resistance connected to said first pair of arm junction points of said Wheatstone bridge and electrical connections for connecting the said standard source to said first pair of arm junction points of said Wheatstone bridge in such a direction that current from said standard source cannot iiow through said bridge, above-said voltages and resistance values being chosen so as to fulfill the condition;

eiR (T2-143) -1-11213=e2RT3 2. A device as in claim 1, wherein the connecting circuit is a manually operated switch or telegraph key.

3. A device as in claim necting circuit is a telegraphic modulator.

4. A device as in claim 1, wherein the conv necting circuit is a three-direction switch, one of the directions of which corresponds to an auxiliary source of Zero electromotive force.

5. A device as in claim 1, wherein one single auxiliary source is used and wherein the connecting circuit consists in a plurality of resistances and in a switch arranged in such a way that operation of said switch reverses the Voltage at the terminals of said connecting circuit.

6. A device as in claim 1, wherein at least one of the auxiliary sources, connecting circuit and second resistance are placed at a point remote from the rest of the installation, to which they are connected by means of a two-conductor line.

7. A device as in claim l, wherein the same source of standard direct-current voltage is used simultaneously in several installations.

8. A device as in claim l, applicable in the case Where the working circuit is a reactive circuit, wherein at least one of the resistances of the device is replaced by a reactive impedance.

RAYMOND JACQUES CHARLES ROQUET.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,825,304 Burnside Sept. 29, 1931 1,951,148 Grinsted Mar. 13, 1934 FOREIGN PATENTS Number Country Date 358,058 Italy Apr. 5, 1938 710,052 Germany Sept. 2, 1941 l, wherein the con. 

